Iíve noticed that that there is often a brown slurry that I think leaks from the rotors after cleaning the wheels which are the 19 inch OEMs with BMW wheel cleaner. Iíve found that by directing the hose stream into the rotor vent holes that it seems to rinse the slurry out and stops it leaking a bit of water and staining the wheels when parking it after a wash. I presume that directing the hose stream into the rotor vent holes is OK as long as the rotors have cooled down ? Anyone else has this problem though ? Itís a pain when you come back later and see the brown slurry stain.